1. Field of the Invention
The present invention relates to a take-up motion control system for a loom, capable of driving a cloth roller, i.e., winding roller, by a controllable motor to take up cloth woven on the loom in a roll of cloth, and of controlling the tension of the cloth by a program according to the variation of the diameter of the roll of cloth.
2. Description of the Related Art
A known technique disclosed in JP-A No. 60-17151 interlocks a cloth roller, i.e., a winding roller, with a drive shaft by a friction clutch, which serves as a mechanical brake, including a friction plate and a pressure plate. The pressure plate is pressed against the friction plate by an appropriate pressure so that the friction plate and the pressure plate may properly slip relative to each other and a proper braking force may be generated. The driving force of the main shaft of the loom may be transmitted to the cloth roller to rotate the cloth roller by a predetermined torque.
This known technique measures change in the diameter of the roll of cloth mechanically, and adjusts the pressure pressing the pressure plate against the friction plate mechanically according to the change of the diameter of the roll of cloth to control the cloth tension by changing the torque of the drive shaft for driving the cloth roller. The relation between the cloth tension F, the torque T of the drive shaft and the radius R of the roll of cloth is expressed by F=T/R.
Even if the torque of the drive shaft for driving the cloth roller is controlled mechanically according to the change of the diameter of the roll of cloth by this known technique, the cloth tension cannot be properly adjusted according to the variation of the diameter of the roll of cloth and, consequently, the cloth is liable to be creased. If creases are defects in the cloth, the cloth cannot be woven in a satisfactory quality unless the braking force is adjusted while the loom is in operation.
The braking force can be adjusted by controlling the mechanical brake according to the diameter of the roll of cloth by an actuator, such as apneumatic cylinder actuator. However, the ability of the mechanical brake deteriorates with time and the braking performance of the mechanical brake changes as the components thereof are abraded. Therefore, the mechanical brake needs periodic maintenance. The braking force can be generated by a powder clutch, and can be controlled by electrically controlling the powder clutch. However, the performance of powder included in the powder clutch changes with time and the powder clutch needs periodic maintenance.
A known technique disclosed in JP-U No. 52-21807 suspends a cylindrical member, i.e., a pressure roller, having a length greater than the width of a roll of cloth formed by rolling cloth so as to press the roll of cloth to roll the cloth around a cloth roller in a uniform, satisfactory shape. The pressure roller is pressed against the roll of cloth by its own weight or by elastic members, such as springs. Thus, the cloth is rubbed by the pressure roller before the same is taken up on the cloth roller. The pressure roller applies pressure uniformly to the entire roll of cloth as the cloth roller rotates to prevent the formation of creases in the cloth rolled in the roll of cloth.
Since the pressure roller applies a fixed pressure to the roll of cloth regardless of different weaving conditions for different types of cloth, the pressure roller is unable to prevent the formation of creases in the cloth under some weaving conditions. Since the pressure applied to the roll of cloth remains constant regardless of the variation of the diameter of the roll of cloth, an appropriate pressure, which must be varied according to the diameter of the roll of cloth, cannot be applied to the roll of cloth having a variable diameter and hence creases are liable to be formed in the rolled cloth.
A plurality of pressure rollers respectively having different weights may be selectively used according to weaving conditions to prevent the formation of creases in the rolled cloth. However, management of parts necessary for the selective use of the plurality of pressure rollers is troublesome and is practically infeasible.
Accordingly, it is a first object of the present invention to achieve the appropriate control of winding tension exerted on cloth being taken up in a roll of cloth on a cloth roller according to the change of the diameter of the roll of cloth without requiring any periodic maintenance work.
The cloth roller is driven for rotation by a torque-controllable motor to control tension exerted on the cloth by a program control mode according to the change of the diameter of the roll of cloth formed by rolling the cloth on the cloth roller.
According to a first aspect of the present invention to achieve the first object of the present invention, a take-up motion control system for controlling a take-up motion included in a loom comprises: a torque-controllable motor for driving a cloth roller, a diameter measuring device capable of providing an electric signal representing the diameter of a roll of cloth formed by winding cloth around the cloth roller, and a motor controller capable of controlling the torque-controllable motor according to a control program on the basis of the electric signal provided by the diameter measuring device and representing the diameter of the roll of the cloth.
The take-up motion control system according to the first aspect of the present invention executes the tension control program for controlling the torque-controllable motor on the basis of the electric signal representing the diameter of the roll of cloth to adjust the tension exerted on the cloth properly according to the diameter of the roll of cloth. Thus, the formation of creases in the cloth rolled in the roll of cloth can be prevented and any maintenance work is not necessary because the take-up motion control system does not include any device subject to deterioration with time, such as a mechanical brake.
In the take-up motion control system according to the first aspect of the present invention, proper tensions are determined for different diameters of the roll including a minimum diameter at the start of winding the cloth and a maximum diameter at the end of winding the cloth according to weaving conditions, and a tension control program for controlling tension exerted on the cloth according to the variation of the diameter of the roll from the minimum to the maximum diameter is created. Since the tension control program for controlling the tension exerted on the cloth according to the variation of the diameter of the roll from the minimum to the maximum diameter is created, appropriate tensions can be exerted on the cloth according to the diameter of the roll of cloth. Hence, the formation of creases in the cloth rolled in the roll of cloth can be prevented even if the cloth is of a delicate type.
In the take-up motion control system according to the first aspect of the present invention, a graph indicating the relation between the diameter of the roll of cloth and the tension may be created on the basis of the tension control program, and the set tensions may be changed by shifting a point or a line on the graph. Since the set tensions are thus changeable by shifting the point or the line on the graph indicating the relation between the diameter of the roll of cloth and the tension, desired values can be readily set and changed, tension setting work can be achieved in a short time, and dispersion in set tensions between different looms can be prevented.
In the take-up motion control system according to the first aspect of the present invention, a present tension and a present roll of cloth diameter may be measured and displayed. When a present tension and a present roll of cloth diameter are measured and displayed, a tension and a diameter when the cloth rolled in the roll of cloth is creased can be recognized, and the set values can be properly changed to prevent the formation of creases in the cloth rolled in the roll of cloth.
In the take-up motion control system according to the first aspect of the present invention, the tension control program specifies set tensions individually for a state where the loom is in operation and a state where the loom is stopped, changes from a control mode using the set tensions for the state where the loom is in operation to a control mode using the set tensions for the state where the loom is stopped in a set time when the loom is stopped, and changes from the control mode using the set tensions for the state where the loom is stopped to the control mode using the set tensions for the state where the loom is in operation in a set time when the loom is started. Thus an appropriate tension can be exerted on the cloth in both the state where the loom is in operation and the state where the loom is stopped, and hence the formation of creases in the cloth at the start of the loom can be prevented.
In the take-up motion control system according to the first aspect of the present invention, the cloth roller may be capable of being rotated in either a normal direction or a reverse direction by operating a switch while the loom is stopped. The cloth roller may also be capable of being stopped automatically after the cloth roller has been rotated in the normal or the reverse direction for a predetermined time or after the cloth roller has been rotated through an angle corresponding to a predetermined length of the cloth. When the cloth roller can be rotated in the normal or the reverse direction by operating the switch while the loom is stopped, and when the cloth roller can be automatically stopped after the same has been rotated for the predetermined time or through the angle corresponding to the predetermined length of the cloth, the cloth will not be damaged by the excessive rotation of the cloth roller.
In the take-up motion control system according to the first aspect of the present invention, the cloth roller may be reversed for a predetermined time or through a predetermined angle to slacken the cloth on the loom upon the coincidence of a count counted by a pick counter with a predetermined number. Since the cloth roller is reversed after a predetermined length of cloth has been woven and the loom has been stopped to slacken the cloth on the loom, the roll of cloth can be unloaded from the loom by an automatic roll of cloth unloading operation.
A second object of the present invention is properly controlling pressure applied to a roll of cloth formed by winding a woven cloth by a pressing member according to weaving conditions and the diameter of the roll of cloth.
The pressing member pressed against the roll of cloth is driven by an actuator while the cloth is being wound around a cloth roller. The actuator is controlled according to weaving conditions or according to weaving conditions and the diameter of the roll of cloth to control the presser applied by the pressing member to the roll of cloth.
According to a second aspect of the present invention to achieve the second object of the present invention, a take-up motion control system for controlling a take-up motion for winding cloth around a cloth roller in a roll on a loom comprises: a pressing member placed in contact with a circumference of the roll wound on the cloth roller with its axis in parallel to that of the cloth roller, an actuator for pressing the pressing member against the roll and applying an adjusted pressure to the roll by the pressing member, and a take-up controller for controlling the actuator to adjust the pressure applied to the roll by the pressing member according to weaving conditions. The pressing member may have a length shorter than the width of the cloth or may consist of a plurality of segments. The actuator may be a pressure-controlled cylinder actuator operated by fluid pressure, a torque-controllable motor whose torque is controllable or an electromagnetically controlled solenoid actuator. Weaving conditions include the type of the cloth, weaving speed and such.
The controller of the take-up motion control system according to the second aspect of the present invention drives the actuator according to weaving conditions to apply an adjusted pressure to the circumference of the roll by the pressing member. Since the pressure applied to the roll is thus adjusted properly according to weaving conditions, the formation of creases in the cloth wound in the roll of cloth can be surely prevented.
According to a third aspect of the present, a take-up motion control system for controlling a take-up motion for winding cloth around a cloth roller in a roll on a loom comprises: a pressing member placed in contact with a circumference of the roll wound on the cloth roller with its axis in parallel to that of the cloth roller, an actuator for pressing the pressing member against the roll and applying an adjusted pressure to the roll by the pressing member, a diameter measuring device capable of providing an electric signal representing information about a diameter of the roll wound on the cloth roller, and a take-up controller for controlling the actuator according to weaving conditions to apply an adjusted pressure to the roll by the pressing member and executing a control program to control the actuator on the basis of the electric signal provided by the diameter measuring device. The information about the diameter of the roll is a measured diameter of the roll or a calculated diameter of the roll calculated on the basis of the length of the cloth woven on the loom or the number of picks inserted in the cloth woven on the loom. Operations for controlling the actuator according to the control program includes changing actuator driving mode on the basis of a program designed according to the diameter of the roll.
The controller of the take-up motion control system according to the third aspect of the present invention drives the actuator according to weaving conditions to apply an adjusted pressure to the circumference of the roll by the pressing member, and controls the operation for driving the actuator according to the control program on the basis of the diameter of the roll. The pressure applied to the roll can be properly adjusted according to the diameter of the roll, and the formation of creases in the cloth wound in the roll of cloth can be prevented from the start to the end of winding the cloth around the cloth roller.
In the take-up motion control system according to the second or the third aspect of the present invention, proper set pressures to be applied to the roll may be determined respectively for different diameters of the roll, such as diameters of the roll respectively at the start, the middle and the end of winding the roll, for weaving conditions. In addition, a pressure control program for controlling the pressure to be applied to the roll according to the change of the diameter of the roll may be created on the basis of those set pressures. When the proper set pressures are thus determined respectively for different diameters of the roll for weaving conditions, and the pressure control program for controlling the pressure to be applied to the roll is created on the basis of those set pressures, a proper pressure can be applied to the roll according to the diameter of the roll of cloth. Hence, the formation of creases in the cloth wound in the roll of cloth can be prevented even if the cloth is of a delicate type.
In the take-up motion control system according to the second or the third aspect of the present invention, a graph indicating the relation between the diameter of the roll and the pressure to be applied to the roll may be created on the basis of the pressure control program, and the set pressures maybe changed by shifting a point or a line on the graph. Since the set pressures are thus changeable by shifting the point or the line on the graph indicating the relation between the diameter of the roll and the pressure to be applied to the roll, desired values can be readily set and changed, pressure setting work can be achieved in a short time, and dispersion in set pressures between different looms can be prevented.
In the take-up motion control system according to the second or the third aspect of the present invention, a current pressure applied to the roll of cloth and a current diameter of the roll of cloth (length of the cloth woven on the loom or the number of picks) may be measured and displayed. When a current pressure applied to the roll and a current diameter of the roll are measured and displayed, a pressure applied to the roll and a diameter of the roll when the cloth rolled in the roll is creased can be recognized, and the set values can be properly changed to prevent the formation of creases in the cloth rolled in the roll.
In the take-up motion control system according to the second or the third aspect of the present invention, the pressure control program may specify set pressures individually for a state where the loom is in operation and a state where the loom is stopped, may change from a control mode using the set pressures for the state where the loom is in operation to a control mode using the set pressures for the state where the loom is stopped in a set time when the loom is stopped, and may change from the control mode using the set pressures for the state where the loom is stopped to the control mode using the set pressures for the state where the loom is in operation in a set time when the loom is started. Thus an appropriate pressure can be applied to the roll in both the state where the loom is in operation and the state where the loom is stopped, and hence the formation of creases in the cloth at the start of the loom can be prevented.
In the take-up motion control system according to the second or the third aspect of the present invention, a pressure applying operation of the pressing member for applying a pressure to the roll may be stopped and started by manually operating a switch. The control of the pressure applying operation by the manual operation of the switch facilitates work for unloading the roll of cloth from the loom.
In the take-up motion control system according to the second or the third aspect of the present invention, the pressure applying operation of the pressing member for applying a pressure to the roll may be stopped automatically upon the coincidence of a count counted by a pick counter with a predetermined number. Since the loom is stopped and the pressure applied to the roll of cloth is removed automatically upon the coincidence of the count counted by the pick counter with the predetermined number, the roll can be unloaded from the loom by an automatic unloading operation.